This is, essentially, a story fighting its need to convey a lot of information to you. It is formatted so the words are very dense on a page, more like an actual book than the cleanly separated paragraphs one would be used to from ff.net; similarly, there is a very high density of information in the story. There are no bits of pointless fluff; everything is meant to tell you something, and it's usually clear what. This makes it more of a grind to read, but definitely a rewarding experience.
The characters are not perfect renditions of themselves; their personalities have been suitably altered to reflect their experiences in this world rather than the one of NGE, but they remain fundamentally the same. In the end this change enhances, rather than detracts from, the story.
Unless you have serious troubles with either the density of the story or its general concept, you'll very likely enjoy this.